“Modified plugin file” Warning

I got this yesterday from wordfence: “Modified plugin file: wp-content/plugins/wp-postratings/includes/postratings-stats.php

Filename: wp-content/plugins/wp-postratings/includes/postratings-stats.php
File Type: Plugin
Issue First Detected: 9 hours 30 mins ago.
Severity: Warning
Status New

This file belongs to plugin “WP-PostRatings” version “1.84.1” and has been modified from the file that is distributed by www.ads-software.com for this version. Please use the link to see how the file has changed. If you have modified this file yourself, you can safely ignore this warning. If you see a lot of changed files in a plugin that have been made by the author, then try uninstalling and reinstalling the plugin to force an upgrade. Doing this is a workaround for plugin authors who don’t manage their code correctly. [See our FAQ on https://www.wordfence.com for more info] ”
As the plugin wasnt update Im asking if this is not modified by malicious code on my website?
Here are the two modified files:
Old: 104 wp_cache_add( $cache_key, $most_rated, $cache_group, HOUR_IN_SECONDS );
Modified: 104 wp_cache_add( $cache_key, $most_rated, $cahce_group, HOUR_IN_SECONDS );

Old: AND $where ORDER BY $order_by DESC, ratings_users DESC LIMIT %d",
Mod: AND $where ORDER BY $order_by DESC, ratings_users DESC LIMIT %s",
Thanks!